Theory and research in language acquisition is shifting the focus from syntactic aspects to semantic and cognitive correlates of the production and comprehension of language. The purpose of the proposed research is to determine if pre-linguistic and early linguistic infants make cognitive distinctions which correspond to linguistically defined semantic distinctions, and whether such distinctions are related to the comprehension and production of language by the infants. Preliminary studies indicate that infants as young as 14 months attend discriminatively to changes in events protrayed with colored film. It is proposed to use film portraying appropriate events as stimulus material and visual fixation and heart rate as indices of an attentional response to assess whether infants will discriminate between and within the semantic categories of action role (agentive and dative), locative, instrumental and objective. Special attention will be given the action role category because of its seeming priority in early linguistic performance. It is also proposed to present infants simultaneously with filmed visual input and an instrumental choice of linguistic audio input so that the infant can select one of the audio inputs as narration of the visual event. It is hoped that the choice will provide data relevant to inferences regarding the relation between cognitive and semantic distinctions.